Drying devices



April 16, 1968 E. WEBER 3,378,131

DRYING DEVICES Filed Feb. 1, 1967 r 5 Sheets-Sheet 1 Fig.1

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E I 4' 0 1L We 5 k April 16, 1968 E. WEBER 3,378,131

DRY ING DEVICES April 16, 1968 E. WEBER 3,378,131

DRYING DEVICES Filed Feb. 1, 1967 5 sheetsrsheet Inventor: EFLCZL W'ebervffi w 5 1 44 2 fi Arm,

United States Patent 0 "ice 3,378,131 DRYING DEVICES Erich Weber,Biutenstrasse It), 13 Munich, Germany Filed Feb. 1, 1967, Ser. No.613,358 Claims priority, application (olzrmany, Feb. 4, 1966,

W 4 7 Claims. (Cl. 198-434) ABSTRACT OF THE DISCLOSURE The inventionrelates to devices for drying fiat printed sheets such as sheets ofpaper, cardboard, synthetic resin, millboard, sheet metal, or wood. Whensheets of such materials are still wet after leaving the printingmachine, for example, a screen printing machine, it is a known practiceto lay the sheets with their printed side upwards on a conveyor belt andonly to invert the sheets or stack them when the printing ink or lacqueris completely dry, such a drying process requiring a considerable timeand therefore requiring the use of a long conveyor belt.

Drying devices in the form of horizontally running conveyor belts havethe disadvantage of requiring a large amount of floor space andvertically travelling ones have been proposed in order to reduce theamount of floor space needed, though their height is of course limitedby the height of the building in which they are used. One suchpreviously proposed drying device in the form of a vertically runningconveyor uses endless sprocket chains running over upper and lowersprocket wheels and provided with carriers for the printed sheets. Theconveyor chains first move the sheet carriers upwards, then turn themover and move them down again. A disadvantage is that the turning overcauses the sheets to rest on their printed surfaces on the descendingcarriers so that if smearing is to be avoided the sheets must be drybefore they are turned over and the descending limb of the conveyor withits carriers does not serve for drying. Although attempts have been madeto avoid the turning over of the sheets at the top end of the conveyor,such conveyors are complicated in construction, expensive and notentirely reliable in use.

One object of the present invention is to provide a sheet drying devicehaving at least one chain conveyor which has ascending and descendinglimbs with carriers for sheets to be dried, in which the transfer ofsheets from the top of the ascending group of carriers to the top of thedescending group of carriers is achieved in a simple manner without thesheets being inverted. A further object of the invention is to provide asheet drying device which takes up little space and has a large dryingcapacity.

Yet a further object of the invention is to provide drying devices whichcan be easily connected together in tandem so that sheets areautomatically transferred from one drying device to the following onefor further drying.

A still further object of the invention is to provide a drying device ordrying installation which is suitable for use with automaticallyoperating printing machnery.

The present invention consists in a device for drying printed sheets,comprising a link-type sprocket conveyor chain having ascending anddescending limbs, chain guide 3,378,131 Patented Apr. 16, 1968 means atthe top and bottom of the limbs, a frame carrying the guide means, meansfor driving the chain conveyor, sheet carriers attached to links of thesprocket chain 50 as to project at an agle from the limbs of the chain,means for laying sheets on the carriers near the bottom of the chain,means for removing sheets from the carriers of the descending limb ofthe conveyor chain, the carriers sloping in such a manner that adjacentto the top of the conveyor chain sheets tend to slide obliquelydownwards from a carrier in a delivery position near the top of theascending chain limb across on to a carrier in a receiving position nearthe top of the descending chain limb, the carriers in. the receiving anddelivery positions being approximately coplanar, the drying devicefurther comprising a transfer conveyor for promoting movement of sheetsfrom a carrier in the delivery position to a carrier in the receivingposition, and means for causing the spacings between, on the one hand, acarrier in the delivery position and a carriage higher up, and, on theother hand, a carrier in the receiving position and a carrier higher up,to be wider than the spacings between carriers in the ascending anddescending limbs of the conveyor chain, the wider spacings providinggaps through which sheets can pass on the transfer conveyor from acarrier in the delivery POSltlOl'l to a carrier in the receivingposition.

It will be seen that with a machine or device as defined in the lastpreceding paragraph there is no inversion of the sheets on transfer fromthe top of the ascending conveyor limb to the top of the descending one,so that drying need not be completed in the ascending limb.

The limbs of the conveyor chain can conveniently be inclined to thevertical.

In accordance with a further feature of the invention, the drying devicecan comprise two horizontally spaced sprocket wheels at the top of theconveyor chain limbs for causing the conveyor chain to extend in astraight line between these sprockets.

The transfer conveyor can be in the form of a conveyor belt.

In a preferred embodiment of the invention the drying device comprisestwo such sprocket chains, approximately horizontal bars extendingbetween the chains and forming parts of the carriers, and spacer partswhich carry the bars on the conveyor chain links, the spacer partsholding the bars some distance from the links. The device can be sodesigned that the spacer parts are replaceable by spacer parts of adifferent size.

In accordance with a further feature of the invention, a part of thedescending limb of the conveyor chain extending from the sheet removingmeans to the bottom of ihe sprocket chain is set at an angle to theascending chain irnb.

The invention also consists in an installation comprising two or moredrying devices in accordance with the invention, both inclined at thesame angle to the vertical, means being provided for transferring sheetsfrom the descending chain limb of one device to the ascending conveyorchain limb of the other device.

The invention is now described with reference to the attached drawings.

FIG. 1 shows a drying device in accordance with the invention from theside.

FIG. 2 shows two drying devices of the construction shown in FIG. 1arranged to form an installation in which sheets are dried first on onedrier and then on the second one.

FIG. 3 is a partial section, on a large scale, of the top part of thedrying device shown in FIG. 1.

As shown more particularly in FIGS. 1 and 3, the dry ing devicecomprises a sprocket chain conveyor frame 1 which is inclined to thevertical and is mounted on a base 2 with which it is additionallyconnected by a stay or frame 3. On each side of the frame 1, I provide alinktype sprocket conveyor chain 4, and each of the two such chains runsat its top end over two horizontally spaced sprocket wheels so that thetop part of each conveyor chain extends in an approximately straightline between the sprocket wheels 5. At the bottom of the drying devicethe conveyor chains pass over further sprocket wheels which are notspecially shown in the drawings. The sprocket wheels constitute chainguide means.

Each sprocket chain comprises an ascending limb running on the left-handside of the frame 1 in the upward direction A, while on the other,right-hand side it forms a descending limb running in the downwarddirection R. The links of the chain have sheet carriers 6 fixed to themfor carrying printed sheets 7 to be dried. In order to mount thecarriers 6 on the chain links, the chain link halves 8 have bent-overportions 9 perpendicular to the planes of the sprocket chains andcarrying spacer parts 10 with bolts 11 which fix horizontal bars 13 inthe form of tubes with flattened ends to the spacer parts 10. Each bar13 is connected at its ends to the spacer 10 on the two conveyor chains.Reference numeral 14 indicates nuts on bolts 11, the latter extendingthrough the spacer parts 10. The bars 13, which form parts of thecarriers 6, are therefore arranged like the rungs of a ladder having thesame pitch or spacing on the ascending limb of the conveyor chains asthe links of the chain, though, if required, carriers 6, 13 could bearranged on only every other or every third conveyor chain link insteadof on every one.

The carriers 6 can for example be in the form of round metal rod or wirewelded or otherwise fixed to the bars 13. Each bar 13 carries severalsuch rods, for example 6, arranged at equal distances along the lengthof the bar in the manner of prongs. The ends of the rods remote from thebars 13 are not connected together.

Owing to the use of the spacer parts 10, which can. be replaced byothers of different lengths, the centre to centre spacing of the bars 13is greater than the chain link pitch in those parts where the chain iscurved. In the straight part of the conveyor chain between the sprocketwheels 5, there is a spacing s between bars 13 in accordance with thelink pitch of the chain and the diameter of the bars 13. At the top ofthe ascending limb of the conveyor chain Where a carrier 6 moves fromthe sheet delivery position (6, to be described below) to the positionin which it is approximately vertical (see FIG. 1), there is aconsiderable widening of the bar spacing to a value S. Similarly thereis a wider spacing between the bar of the carrier in the receivingposition marked 6 and the preceding higher up carrier. The provision ofthese wider spacings S enables a printed sheet 7 to slide off thecarrier in the delivery position 6', as indicated by arrow T, on to thecarrier in the receiving position 6" at the top of the descending limbof the conveyor chain, without there being any danger of the topsurface, which carries the wet printed image, being smeared or streakedby bars 13 at the very top of the drying device. The carriers in thedelivery position 6' and the receiving position 6" are approximatelycoplanar. In order to make the frame 1 more rigid, it is provided withat least one transverse strut 15 (see FIG. 3) on which an angle piece 16is welded, the latter having bolts 17 carrying a plate 18. The two flatpieces or plates 18, one being provided on each side of the device,carry bearings for the shafts 19 of rollers 20 which carry a belt 21forming a transfer conveyor, moving in the direction of the arrow. Thetransfer conveyor promotes the movement of a sheet 7 in the obliquedownward direction T from a carrier 6' to 'a carrier in the receivingposition 6".

In order to prevent the inclined sheets 7, which are moving upwards inthe direction A and downwards in the direction R, from sliding oil? thecarriers 6, abutments 22 (see FIGS 1 and 2) are provided for thedescending sheets, while similar abutments, not specially shown, are

provided for the ascending sheets. The abutments 22 are held in place bya bracket 23.

At the top of the conveyor chains, however, the abutments for preventingthe ascending sheets 7 from sliding downwards to the right off thecarriers 6 are discontinued, so that a sheet can slide from the carrierin the delivery position 6' in the direction of the arrow T on to thecarrier in the receiving position 6" until it is halted by the abutments22. This sliding movement of the sheet is initiated by the slope of thecarrier in the delivery position 6. The sheet then crosses the gapbetween the carrier in the delivery position and transfer conveyor whichtransports on to the carrier in the receiving position 6" on which thesheet slides until it comes to rest against the abutments 22.

In operation, printed sheets are delivered in the direction of the arrowE (see FIG. 1) and are deposited on the series of bars 24 extendingbetween the rods of the carriers 6. The bars 24 are fixed in positionand are carried by brackets 25. The rods of a carrier 6 moving upwardsthen pass between the bars 24 and lift the printed sheet resting on themupwards in the direction A, the sheet being prevented from sliding offthe carrier by the abutments (not shown) previously referred to. At thetop of these abutments, the sheet can then slide downwards to the rightfrom the carrier in the delivery position 6' on to the transfer conveyorwhich promotes its sliding movement on to the carrier in the receivingposition 6". From this position the printed sheet to be dried is moveddownwards in the direction R and is taken up by a sheet removing meansin the form of a conveyor belt 26 acting in the direction P.

The conveyor chains 4 are driven by drive means in the form of anelectric motor 27 which is switched on and off automatically so as tooperate the chains 4, with which it is connected by chain 28, in steps.A further electric motor 29 drives the transfer conveyor by means of abelt or the like 30. An electric motor 31 is provided for driving thesheet removing belt 26, via a transmission 32.

At the position at which the sheets 7 are removed from the carriers 6,the latter are caused to fan out to make a larger gap owing to the factthat the part of the descending limb of the conveyor chains extendingfrom the position at which sheets are removed by belt 26 to the bottomof the conveyors makes an angle with ascending limbs of the conveyorchains, as is indicated by reference numeral 4'. This facilitates theoperation of the belt 26.

In the installation shown in FIG. 2, two substantially similar dryingdevices of the construction shown in FIG. 1, are arranged in tandem andboth are inclined at the same angle to the vertical. Means including thebelt 26 serve to transfer the sheets 7 from the descending limb of theconveyor chain of the left-hand drying device in the direction of thearrow P on to the receiving bars 24 of the second drying device of theinstallation, so that the sheets are manipulated by the second dryingdevice in exactly the same manner as by the first device. The sheetremoving means (belt 26) of the second, right-hand, drying devicedeposits on a suitable stand or the like. Owing to the inclination ofthe two devices to the vertical, the installation shown in FIG. 2requires less floor space than two separate drying devices. The devicescan be arranged so that they can be easily disconnected for useseparately. If required more than two drying devices can be connectedtogether in a train for drying sheets.

Various modifications can be made in the device described within thescope of the following claims.

What I claim is:

1. A device for drying printed sheets, comprisingat least one link-typesprocket conveyor chain having ascending and descending limbs, chainguide means at the top and bottom of the limbs, a'frame carrying theguide means, means for driving the chain conveyor, sheet carriersattached to links of the sprocket chain so as to project at an anglefrom the limbs of the chain, means for laying sheets on the carriersnear the bottom of the chain, means for removing sheets from thecarriers of the descending limb of the conveyor chain, the carrierssloping in such a manner that adjacent to the top of the conveyor chainsheets tend to slide downwards from a carrier in a delivery positionnear the top of the ascending chain limb across on to a carrier in areceiving position near the top of the descending chain limb, thecarriers in the receiving and delivery positions being approximatelycoplanar, the drying device further comprising a transfer conveyorpositioned adjacent to top of the ascending and descending chain limbsfor promoting movement of sheets from a carrier in the delivery positionto a carrier in the receiving position, and means for causing thespacings between, on the one hand, a carrier in the delivery positionand a carrier higher up, and, on the other hand, a carrier in thereceiving position and a carrier higher up, to be wider than thespacings between carriers in the ascending and descending limbs of theconveyor chain, the wider spacings providing gaps through which sheetscan pass on the transfer conveyor from a carrier in the deliveryposition to a carrier in the receiving position.

2. A device according to claim 1 in which the limbs of the conveyorchain are inclined to the vertical.

3. A device according to claim 1 further comprising two horizontallyspaced sprocket wheels at the top of the conveyor chain limbs forcausing the conveyor chain to extend between them in a straight line.

4. A device according to claim 1 in which the transfer conveyor is aconveyor belt.

5. A device according to claim 1 comprising two such sprocket chains,approximately horizontal bars extending between the sprocket chains andforming parts of the carriers, and spacer parts which carry the bars onthe conveyor links, the spacer parts holding the bars some distance fromthe links.

6. A device according to claim 5 in which the spacer parts arereplaceable by spacer parts of different sizes.

7. A device according to claim 1 in which a part of the descending limbof the sprocket conveyor chain extending from the sheet removing meansto the bottom of the sprocket conveyor chain is set at an angle to theascending limb of the sprocket chain.

References Cited UNITED STATES PATENTS 370,969 10/1887 Rheutan 198-1341,853,478 4/1932 Vincent 198-134 RICHARD E. AEGERTER, Primary Examiner.

